MAPK8 and neoplasm: In this study we show in Drosophila that; 1) the BTB-ZF transcription factor Abrupt acts as a potent oncogene when combined with the loss of scrib in the eye/antennal disc; 2) scrib−+ab epithelial tumours are associated with an earlier developmental state; 3) impaired Hippo signalling in scrib mutants is a key factor in mediating cooperative overgrowth with ab overexpression; and 4) ab can promote tumour overgrowth, but not invasion, independently of JNK signalling.